Regional Public Health Laboratory Kennemerland

Haarlem, Netherlands

Regional Public Health Laboratory Kennemerland

Haarlem, Netherlands
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Schalk J.A.C.,National Institute for Public Health and the Environment | van Leeuwen A.E.D.,National Institute for Public Health and the Environment | Lodder W.J.,National Institute for Public Health and the Environment | de Man H.,Institute for Risk Assessment science | And 3 more authors.
Applied and Environmental Microbiology | Year: 2012

Viable Legionella pneumophila bacteria were isolated by amoebal coculture from pluvial floods after intense rainfall and from water collected at sewage treatment plants. Several isolated L. pneumophila strains belonged to sequence types that have been previously identified in patients. © 2012, American Society for Microbiology.


Casati S.,Cantonal Institute of Microbiology | Conza L.,Cantonal Institute of Microbiology | Bruin J.,Regional Public Health Laboratory Kennemerland | Gaia V.,Cantonal Institute of Microbiology
Clinical Microbiology and Infection | Year: 2010

Data on the presence of Legionellae outside the aquatic environment are scarce. Alternative ecosystems that could act as a reservoir for Legionella spp. have been investigated to identify unconventional contaminated substrates that are able to produce bioaerosols. We considered eight green waste collection sites including three composting facilities. Legionella pneumophila sg 1-15, Legionella bozemanii, Legionella cincinnatiensis, Legionella jamestowniensis, Legionella micdadei and L. oakridgensis were isolated from samples taken at six of the eight sites. The degree of contamination ranged from 103 to 108 CFU/g. Compost facilities appear to comprise an important reservoir for Legionellae. © 2009 The Authors. Journal Compilation © 2009 European Society of Clinical Microbiology and Infectious Diseases.


Euser S.M.,Regional Public Health Laboratory Kennemerland | Nagelkerke N.J.,United Arab Emirates University | Schuren F.,TNO | Jansen R.,Regional Public Health Laboratory Kennemerland | Den Boer J.W.,Regional Public Health Laboratory Kennemerland
PLoS ONE | Year: 2012

Background: Legionella, the causative agent for Legionnaires' disease, is ubiquitous in both natural and man-made aquatic environments. The distribution of Legionella genotypes within clinical strains is significantly different from that found in environmental strains. Developing novel genotypic methods that offer the ability to distinguish clinical from environmental strains could help to focus on more relevant (virulent) Legionella species in control efforts. Mixed-genome microarray data can be used to perform a comparative-genome analysis of strain collections, and advanced statistical approaches, such as the Random Forest algorithm are available to process these data. Methods: Microarray analysis was performed on a collection of 222 Legionella pneumophila strains, which included patient-derived strains from notified cases in the Netherlands in the period 2002-2006 and the environmental strains that were collected during the source investigation for those patients within the Dutch National Legionella Outbreak Detection Programme. The Random Forest algorithm combined with a logistic regression model was used to select predictive markers and to construct a predictive model that could discriminate between strains from different origin: clinical or environmental. Results: Four genetic markers were selected that correctly predicted 96% of the clinical strains and 66% of the environmental strains collected within the Dutch National Legionella Outbreak Detection Programme. Conclusions: The Random Forest algorithm is well suited for the development of prediction models that use mixed-genome microarray data to discriminate between Legionella strains from different origin. The identification of these predictive genetic markers could offer the possibility to identify virulence factors within the Legionella genome, which in the future may be implemented in the daily practice of controlling Legionella in the public health environment. © 2012 Euser et al.


Euser S.M.,Regional Public Health Laboratory Kennemerland | Bruin J.P.,Regional Public Health Laboratory Kennemerland | Brandsema P.,National Institute for Public Health and the Environment RIVM | Reijnen L.,Regional Public Health Laboratory Kennemerland | And 2 more authors.
European Journal of Clinical Microbiology and Infectious Diseases | Year: 2013

Legionnaires' disease (LD) is an acute pneumonia caused by the inhalation or aspiration of aerosols contaminated with Legionella bacteria. The watery environment is considered to be the natural habitat for these bacteria. Therefore, drinking water legislation is used in the primary prevention of LD, focussing on the different water sources to which the general public is exposed. For 10 years, secondary prevention of LD in the Netherlands has been organised using an outbreak detection programme that eliminates potential sources of infection that LD patients have been exposed to during their incubation period. To evaluate the two prevention strategies, we compared the distribution of Legionella pneumophila serogroup 1 genotypes isolated from patient material (n = 179) with the distribution resulting from primary (n = 182) and secondary (n = 60) prevention actions, respectively. The sequence type profiles were generated using the HiMLST method that employs next generation sequencing. We found that genotypes collected during primary prevention differ to a large extent from those isolated from patients. Genotypes collected during secondary prevention efforts had a greater similarity to that of patient isolates, but could be further improved. Our results suggest that primary prevention is not aiming at the correct reservoir, whereas secondary prevention is only partially focussed. It seems that there is a still unknown reservoir. © 2013 Springer-Verlag Berlin Heidelberg.


Brandsema P.S.,National Institute for Public Health and the Environment RIVM | Euser S.M.,Regional Public Health Laboratory Kennemerland | Karagiannis I.,Robert Koch Institute | Den Boer J.W.,Regional Public Health Laboratory Kennemerland | Van Der Hoek W.,National Institute for Public Health and the Environment RIVM
Epidemiology and Infection | Year: 2014

During August and September 2010 an unexpected high number of domestic cases of Legionnaires' disease (LD) were reported in The Netherlands. To examine this increase, patient characteristics and results of source finding and environmental sampling during the summer peak were compared to other domestic cases in 2008-2011. This analysis did not provide an explanation for the rise in cases. A similar increase in LD cases in 2006 was shown to be associated with warm and wet weather conditions, using an extended Poisson regression model with adjustment for long-term trends. This model was optimized with the new data from 2008 to 2011. The increase in 2010 was very accurately described by a model, which included temperature in the preceding 4 weeks, and precipitation in the preceding 2 weeks. These results confirm the strong association of LD incidence with weather conditions, but it remains unclear which environmental sources contributed to the 2010 summer increase. Copyright © Cambridge University Press 2014.


Euser S.M.,Regional Public Health Laboratory Kennemerland
Global health action | Year: 2012

To describe the effects of a broad empowerment programme among female sex workers (FSWs) in Bangalore, India, which seeks to develop the capacities of these women to address the issues that threaten their lives and livelihoods. This study is based on a comprehensive, on-going HIV-prevention and empowering programme, known as Pragati, which reaches out to approximately 10,000-12,000 FSWs in Bangalore each year. The programme has been designed in collaboration with the sex worker community and provides a personalised set of services, which include STI prevention and treatment services, crisis-response facilities, de-addiction services, and microfinance support all of which have been tailored to adequately fulfil each woman's needs. During the period examined by this study, the programme reached out to 20,330 individual FSWs [median (IQR) age 28 (24-35) years]. The programme's personal records of the participating FSWs were used for this descriptive study. Between 2005 and 2010, the number of participating FSWs increased from 2,307 to 13,392. These women intensified their contact with the programme over time: the number of programme contacts increased from 10,351 in 2005 to 167,709 in 2010. Furthermore, data on the effects of crisis-response facilities, de-addiction and microfinance services, condom distribution schemes, and STI diagnosis and treatment showed an accumulating involvement of the participating FSWs in these programme services. This programme, which focuses on social and economic empowerment among FSWs, is successful in reaching and involving the target population.


Euser S.M.,Regional Public Health Laboratory Kennemerland
Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin | Year: 2012

Visiting wellness centres is considered safe and relaxing and might provide health benefits for visitors with certain cardiovascular, dermatological or respiratory diseases. On the other hand, wellness centres could pose health risks, especially with respect to Legionnaires' disease. We investigated the role of wellness centres in the occurrence of Legionnaires' disease by analysing the data of eight years (2002-2010) of source investigation in the Netherlands. There were 15 wellness centres identified as potential sources of infection for a total of 35 Legionnaires' disease patients. Twelve of these centres were positive for Legionella spp.: six for Legionella pneumophila, six for non-pneumophila Legionella spp.. Of the 65 positive environmental samples found during the wellness centre investigations, 41 were derived from shower heads. For two centres, the Legionella pneumophila strains in the collected samples had a genotype that was indistinguishable from the patient isolates. These results show that wellness centres are potential sources of Legionnaires' disease.


Bosch T.,National Institute for Public Health and the Environment | Euser S.M.,Regional Public Health Laboratory Kennemerland | Landman F.,National Institute for Public Health and the Environment | Bruin J.P.,Regional Public Health Laboratory Kennemerland | And 3 more authors.
Journal of Clinical Microbiology | Year: 2015

Legionella is the causative agent for Legionnaires' disease (LD) and is responsible for several large outbreaks in the world. More than 90% of LD cases are caused by Legionella pneumophila, and studies on the origin and transmission routes of this pathogen rely on adequate molecular characterization of isolates. Current typing of L. pneumophila mainly depends on sequence-based typing (SBT). However, studies have shown that in some outbreak situations, SBT does not have sufficient discriminatory power to distinguish between related and nonrelated L. pneumophila isolates. In this study, we used a novel high-resolution typing technique, called whole-genome mapping (WGM), to differentiate between epidemiologically related and nonrelated L. pneumophila isolates. Assessment of the method by various validation experiments showed highly reproducible results, andWGM was able to confirm two well-documented Dutch L. pneumophila outbreaks. Comparison of whole-genome maps of the two outbreaks together with WGMs of epidemiologically nonrelated L. pneumophila isolates showed major differences between the maps, andWGMyielded a higher discriminatory power than SBT. In conclusion,WGMcan be a valuable alternative to perform outbreak investigations of L. pneumophila in real time since the turnaround time from culture to comparison of the L. pneumophila maps is less than 24 h. Copyright © 2015, American Society for Microbiology. All Rights Reserved.


Euser S.M.,Regional Public Health Laboratory Kennemerland | Bruin J.P.,Regional Public Health Laboratory Kennemerland | van der Hoek W.,National Institute for Public Health and the Environment | Schop W.A.,Municipal Public Health Service Rotterdam Rijnmond | den Boer J.W.,Regional Public Health Laboratory Kennemerland
Eurosurveillance | Year: 2012

Visiting wellness centres is considered safe and relaxing and might provide health benefits for visitors with certain cardiovascular, dermatological or respiratory diseases. On the other hand, wellness centres could pose health risks, especially with respect to Legionnaires' disease. We investigated the role of wellness centres in the occurrence of Legionnaires' disease by analysing the data of eight years (2002-2010) of source investigation in the Netherlands. There were 15 wellness centres identified as potential sources of infection for a total of 35 Legionnaires' disease patients. Twelve of these centres were positive for Legionella spp.: six for Legionella pneumophila, six for non-pneumophila Legionella spp. Of the 65 positive environmental samples found during the wellness centre investigations, 41 were derived from shower heads. For two centres, the Legionella pneumophila strains in the collected samples had a genotype that was indistinguishable from the patient isolates. These results show that wellness centres are potential sources of Legionnaires' disease.


Euser S.M.,Regional Public Health Laboratory Kennemerland | Pelgrim M.,Municipal Health Service Hulpverlening Gelderland Midden | Den Boer J.W.,Regional Public Health Laboratory Kennemerland
Scandinavian Journal of Infectious Diseases | Year: 2010

Pontiac fever and Legionnaires' disease are regarded as clinically and epidemiologically distinct diseases, caused by bacteria of the genus Legionella. Although several outbreaks of either Pontiac fever or Legionnaires' disease have been reported, they are rarely seen simultaneously. In this report we describe such a simultaneous outbreak of Pontiac fever and Legionnaires' disease that occurred in the Netherlands. In August 2009, 1 patient with Legionnaires' disease and 3 patients with Pontiac fever, all from a single family, were reported to the Municipal Health Service. All family members had been exposed to the private whirlpool spa in the garden of their home. A sampling investigation by the Legionella Source Identification Unit (LSIU) showed that a sample from the whirlpool spa, as well as a sample from the garden shower and 2 samples from a garden hose were positive for Legionella pneumophila serogroup 1, and genotyping results indicated the AFLP-type 004 Lyon (ST47) to be present in these samples. © 2010 Informa Healthcare.

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